﻿using System.Text;
using System.Security.Cryptography;
using System.IO;

namespace Kwan.Helper.Strings
{
    public class MD5
    {
        #region MD5加密
        /// <summary>
        /// MD5加密
        /// </summary>
        /// <param name="strSource">需要加密的字符串</param>
        /// <returns>MD5加密后的字符串</returns>
        public static string Md5Encrypt(string strSource)
        {
            byte[] bytIn = Encoding.Default.GetBytes(strSource);
            //建立加密对象的密钥和偏移量
            byte[] iv = { 102, 16, 93, 156, 78, 4, 218, 32 };//定义偏移量
            byte[] key = { 55, 103, 246, 79, 36, 99, 167, 3 };//定义密钥
            //实例DES加密类
            using (DESCryptoServiceProvider mobjCryptoService = new DESCryptoServiceProvider())
            {
                mobjCryptoService.Key = iv;
                mobjCryptoService.IV = key;
                using (MemoryStream ms = new MemoryStream())
                using (ICryptoTransform encrypto = mobjCryptoService.CreateEncryptor())
                using (CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Write))
                {
                    //实例MemoryStream流加密密文件
                    cs.Write(bytIn, 0, bytIn.Length);
                    cs.FlushFinalBlock();
                    return System.Convert.ToBase64String(ms.ToArray());
                }
            }
        } 
        #endregion

        #region MD5解密
        /// <summary>   
        /// MD5解密   
        /// </summary>   
        /// <param name="Source">需要解密的字符串</param>   
        /// <returns>MD5解密后的字符串</returns>   
        public static string Md5Decrypt(string Source)
        {
            //将解密字符串转换成字节数组   
            byte[] bytIn = System.Convert.FromBase64String(Source);
            //给出解密的密钥和偏移量，密钥和偏移量必须与加密时的密钥和偏移量相同   
            byte[] iv = { 102, 16, 93, 156, 78, 4, 218, 32 };//定义偏移量   
            byte[] key = { 55, 103, 246, 79, 36, 99, 167, 3 };//定义密钥   
            using (DESCryptoServiceProvider mobjCryptoService = new DESCryptoServiceProvider())
            {
                mobjCryptoService.Key = iv;
                mobjCryptoService.IV = key;
                using (MemoryStream ms = new MemoryStream(bytIn, 0, bytIn.Length))
                using (ICryptoTransform encrypto = mobjCryptoService.CreateDecryptor())
                using (CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Read))
                using (StreamReader strd = new StreamReader(cs, Encoding.Default))
                {
                    return strd.ReadToEnd();
                }
            }
        } 
        #endregion   
    }
}
